Union Pacific 4-8-4 "Northern" Locomotives of the USA

The Union Pacific Railroad bought 45 4-8-4s in three orders from the American Locomotive Company.

The first order of 20 locomotives (road numbers 800 through 819) was delivered in 1937. These were designated Class FEF-1 and were designed by UP's Motive Power Group to have 77" drivers, 24.5 x 32 cylinders, a boiler pressure of 300 psi, and a weight of 465,000 lbs resulting in a tractive effort of 63,611 pounds (63,800 nominal).

The second order of 15 locomotives (road numbers 820 through 834) was delivered in 1939. These locomotives were designated as Class FEF-2. They were designed to have 80" drivers, 25 x 32 cylinders, a boiler pressure of 300 psi, and a weight of 483,000 lbs giving each a tractive effort of 63,750 pounds (63,800 nominal).

The last group of 10, Class FEF-3 were delivered in 1944 and were assigned road numbers 835 through 844. These FEFs (Four-Eight-Four) were designated Class FEF-3 and were very similar to the Class FEF-2's.

Comparing operating costs per mile in 1946:

 NYC NiagaraU.P. #800-844
Other supplies$0.005$0.005
Crew wages$0.1944$0.1944
Vacation allow.$0.0058$0.0058
Social security$0.0175$0.0175
Fixed charges$0.09$0.09
Total Cost/mile$1.22$1.19

The UP 800 Four-Eight-Fours saved UP $300,000/year in costs. The purchase price for these engines was $150,000 in 1944 dollars. The 800s ran about 14,000 miles per month. Today these engines would cost around $10-11 per mile. The 800s cast-steel locomotive frame which replaced many separate parts by one single casting helped maintenance. Information provided by Dan McNaughton.

There are four surviving UP 4-8-4s: number 814 in Council Bluffs, IA; number 833 which was recently moved from Pioneer Park in Salt Lake City, UT to the Ogden Union Station Museum in Ogden, UT; number 838 at UP engine house in Cheyenne, WY and number 844, which is operational, also at UP engine house in Cheyenne, WY.

Roster by Richard Duley

ClassRoad Numbers Year BuiltBuilder

Class Details by Steve Llanso of Sweat House Media

Class FEF-1 (Locobase 8339)

Data from UP 11 - 1946 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Raildata collection. Works numbers were 68808-68826 in August 1937, 68827 in September.

These engines were worked hard in service and responded exceptionally well. They were fitted with unusual tapered main and side rods, which reduced the mass of steel out at the end of the rotary motions. In addition, each wheel crank pin had its own sleeve bearing, which reduced the strain on the main crank pins on each side. These engines were reported as frequently running at above 100 mph.

They arrived in three batches, two (FEF-1 & FEF-3) which had Type A superheaters. These are shown in this entry (FEF-1) and Locobase 8340 (FEF-3). This first set had the smaller drivers 77") and a boiler pressed originally to 260 psi. Leading and trailing truck roller bearings were supplied by SKF while Timken produced those for the driving axles.

FEF-2s had the Type E superheater, which resulted in a very different boiler layout; see Locobase 284.

After diesels bumped the big oil-burners from passenger service, they turned their 80" drivers to freight work. The first was retired in 1954, the last in 1961.

Class FEF-2 (Locobase 284)

Data from UP 11 - 1946 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Raildata collection. Works numbers were 69161-69165 in August 1939, 69166-69172 in September, 69173-69175 in October.

Note that the diagram does not give a grate area, presumably because these were oil burners.

As outlined in Locobase 8339, these 4-8-4s were the premier passenger power on the Union Pacific. When the UP returned to the Alco for more of these enormous locomotives, the builder supplied these 15 with a Type E superheater installation with much more superheater area. The engines arrived with 80" drivers, 300-psi boilers, and roller bearings on all axles. (820-829 had Timken bearings, 830-834 were fitted with SKFs.)

The railroad bought ten more FEFs in 1944; see Locobase 8340. As the railroad dieselized in the 1950s, the FEF-2s gradually left service. The first was retired in 1956, the last in 1962.

Class FEF-3 (Locobase 8340)

Data from UP 11 - 1946 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Raildata collection. Works numbers were 72782-72791 in December 1944.

When World War II traffic levels over-stressed the existing UP passenger-locomotive stud, the railroad returned to Alco for ten more of the FEF design. They might have preferred to buy diesel sets, but those were not available. Instead, Alco produced engines with the power dimensions and driver diameters of the FEF-2 (Locobase 284) under a boiler virtually identical to that of the FEF-1 (Locobase 8339). And like the FEF-1, SKF supplied the leading and trailing truck roller bearings while Timken produced those for the driving axles.

Although delivered with 69.5 sq ft (6.45 sq m) of arch tubes, these were removed in 1945.

The last of the class - 844 - never actually left service. Its 1957-1959 stint of freight work was its last revenue work, but it was reserved for excursion work in 1960. Renumbered for a time as 8444, the locomotive regained its original number in 1969 after the diesel that bore 844 was retired. It was reassigned to excursion work and ran into the 21st Century.

The other 9 were all retired in 1957-1962.

Specifications by Steve Llanso of Sweat House Media
Locobase ID8339 284 8340
RailroadUnion Pacific (UP)Union Pacific (UP)Union Pacific (UP)
Number in Class201510
Road Numbers800-819820-834835-844
Number Built201510
Valve GearWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase21.50'22'22'
Engine Wheelbase49.25'50.92'50.92'
Ratio of driving wheelbase to overall engine wheebase 0.44 0.43 0.43
Overall Wheelbase (engine & tender)97.50'98.42'98.42'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers265840 lbs265200 lbs266490 lbs
Engine Weight460640 lbs478640 lbs486340 lbs
Tender Light Weight384350 lbs416320 lbs421550 lbs
Total Engine and Tender Weight844990 lbs894960 lbs907890 lbs
Tender Water Capacity19764 gals23500 gals23500 gals
Tender Fuel Capacity (oil/coal)6550 gals6000 gals6000 gals
Minimum weight of rail (calculated)111 lb/yard111 lb/yard111 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter77"80"80"
Boiler Pressure300 psi300 psi300 psi
Cylinders (dia x stroke)24.5" x 32"25" x 32"25" x 32"
Tractive Effort63611 lbs63750 lbs63750 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.18 4.16 4.18
Heating Ability
Firebox Area422 sq. ft442 sq. ft442 sq. ft
Grate Area100.20 sq. ft
Evaporative Heating Surface4540 sq. ft4413 sq. ft4225 sq. ft
Superheating Surface1473 sq. ft1900 sq. ft1400 sq. ft
Combined Heating Surface6013 sq. ft6313 sq. ft5625 sq. ft
Evaporative Heating Surface/Cylinder Volume260.01242.73232.39
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation0030060
Same as above plus superheater percentage0037575
Same as above but substitute firebox area for grate area156984172380165750
Power L1438945219441880
Power MT1456.061735.561385.86



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